He said allegations that Mr Habib was involved with terrorist
organisation al-Qaeda warranted his detention.

"This is a very, very serious allegation," Mr Downer said
today.

"Al-Qaeda is the world's most evil terrorist organisation.

"There's a situation where people who are combatants in a
conflict and then are detained are held in detention until the end
of that conflict.

"In those circumstances, people are detained until there's some
process worked through about what to do with them."

Mr Habib arrived at Sydney Airport in a government-chartered jet
today before boarding a small propeller aircraft which took off for
an unknown destination.

He is unlikely to face prosecution in Australia because most
anti-terror legislation started in July 2002, after his capture in
Pakistan.

However, Australia has pledged to monitor Mr Habib as part of
his release to ensure he presented no security threat.

"We've told the Americans we will provide appropriate security
for Australian people," Mr Downer said.

"ASIO and the Australian Federal Police and the New South Wales
police will monitor his activities and we will make sure that at no
time he becomes a threat to the Australian people.

"Anybody who has allegedly been involved in an organisation like
al-Qaeda - which is the world's most evil terrorist organisation -
is somebody who is of great concern to the Australian government
and our priority is the protection of the Australian people.

"I don't think the public expect any less of us than that."

Sydney lawyer Stephen Hopper yesterday said he was gathering
evidence to prove the federal government was aware Mr Habib was
tortured at Guantanamo Bay.

In one instance of the torture alleged by Mr Hopper, a
prostitute stood over Mr Habib and menstruated on him.

Mr Downer denied any Australian involvement or knowledge of the
abuse.

"They can look for what they like. They won't find anything," he
said of Mr Hopper's inquiries.

"We have not a skerrick of evidence that any Australian has been
involved in abusing Mr Habib."